1. a. Field of the Invention
The present invention relates to an apparatus for use in softening hard water, and it particularly relates to an apparatus for softening hard water which is opposite to the case of softening the raw water supplied from service pipes so as to be fit for use in boilers.
2. B. Description of the prior Art
As water for use in boilers, the raw water supplied from service pipes has hitherto been generally employed. However, such raw water has usually a high hardness and is rich in scale-forming ingredients, so that it must be treated for softening. And, to meet this requirement, there have been proposed various apparatuses for softening hard water utilizing ion-exchange resins.
The ion-exchange resin to serve for this purpose is of Na.sup.+ type, and the softening of raw water is supposed to be performed by exchanging metal cation, such as Ca.sup.2.sup.+ or Mg.sup.2.sup.+, contained in said raw water for Na.sup.+. But, with the progress of this softening operation to a certain degree, the ion-exchange resin gets saturated and loses its softening capacity, so that it becomes necessary to suspend the supply of raw water and to supply salt water in place of raw water to thereby activate ion-exchange resin.
Under such circumstances, there have hitherto been proposed various apparatuses for softening hard water so devised as to be capable of performing the softening operation and the ion-exchange resin activation operation concurrently, and these apparatuses can be classified into two types, one type wherein the valve installed in the softening zone is separate from the valve installed in the activation zone and the other wherein these two valves are consolidated into single valve.
However, all of these conventional apparatuses have a drawback that, inasmuch as they are of such construction as requiring direct operation of the valve or valves by the operator and synchronization of said operation with the cycle of activation of ion-exchange resin, they can be handled only by those having thorough knowledge of the construction of said apparatuses as well as how to operate them.